Dado blade RPM Question

[Tim Tyler]

Hello Everyone,

I have a Delta 10" table saw that recommends 10" blades that tolerate 7600 RPM or more.

Recently, I was given a 7" Craftsman adjustable "wobbler" type blade and a Craftsman 7" stacked dado set. Both these sets say 4600 RPM Maximum.

With the shorter 7" blade, is the RPM of my saw in the 4600 range? Is it safe to use my inherited dado blades?

Thanks for any guidance.

Tim

[scott spencer]

Most saws spin at around 3500rpm, though some of the direct drives spin at 4000-4500rpm...it depends on which model you have. The RPM is the same regardless of the diameter of blade. Buy good quality blades, and it shouldn't be a problem either way. It's good practice to stand off to the side of the blade regardless.

[david brum]

You can also look on the ID plate on your table saw's motor in order to see the RPMs.

[John McClanahan]

I highly doubt your saw runs over 4600 rpms. Somewhere around 3450. If the motor pulley looks bigger than the arbor pulley, up to about 4200 rpms. On a contractor saw, I would bet its 3450 rpms. You will be fine.

John

[Lee Schierer]

Just so you know diameter of the blade make no difference on how fast it will rotate. If the arbor turns at 3450 rpm, then any blade placed on it will rotate at 3450 rpm. Check your motor nameplate for its listed rpm then check the relative diameters of the motor and arbor pulleys. If they are the same diameter, the arbor turns at the same rpm listed on the motor nameplate.

[Tim Tyler]

Thank you all for the advice and information.

I had read an older forum post that the blade RPM would be less for a smaller blade. This is obviously an error.

I read the plate on the motor and see the RPM is 3450. I can use the dado blades with no issues.

Thank you all for your help.

Tim

[David Kumm]

It is the tip speed of the tooth into the cut that changes with diameter. That is why a large diameter shaper cutter can travel more slowly yet give a better cut. With a dado the issue is also weight of the spinning blades as they can overpower the arbor assembly of the saw. That is why dados are usually smaller diameter than main blades. Dave